부산대학교 도서관

Our laboratory has demonstrated that maternal nutrition in beef cows can impact uterine blood flow and vascular function of excised placental arteries. However, there is little evidence to suggest that maternal nutrition is impacting capillary number. There is evidence in other species that multi-nucleated cells (i.e., binucleate cells; BNC) in the placenta may produce vasoactive factors. The objective was to test the hypothesis that maternal nutrient restriction followed by early realimentation would increase BNC numbers in the bovine placentome. On d 30 of pregnancy, multiparous, non-lactating cows (620.5 ± 11.3 kg) were assigned to 1 of 2 dietary treatments: control (C;100% NRC; n= 18) and restricted (R; 60% NRC; n= 30). On d 85, cows were slaughtered (C, n= 6; R, n= 6), remained on control (CC; n= 12) and restricted (RR; n= 12), or were realimented to control (RC; n= 11). On d 140, cows were slaughtered (CC, n= 6; RR, n= 6; RC, n= 5), remained on control (CCC, n= 6; RCC, n= 5), or were realimented to control (RRC, n= 6). On d 254, all remaining cows were slaughtered. Placentomes were collected and fixed in formalin. Tissue sections were stained using biotinylated lectin Dolichos Biflorus Agglutinin (DBA), Texas red avidin, and DAPI mounting media to visualize BNC. Using image analysis, BNC number, BNC size, and percentage BNC area per tissue area were determined. While there was no effect of diet (P> 0.11) on any measurement, there was a main effect of day (P< 0.01) where BNC numbers decreased as gestation advanced (572.5, 504.1, 489.1 ± 31.35 for d 85, 140, and 254, respectively). In addition, the BNC size decreased (P< 0.01) from d 85 to 140 of gestation, then increased until d 254 (63.1, 51.8, 65.2 ± 3.0 mm2, respectively). Similarly, the percent BNC area per tissue area decreased (P< 0.01) from d 85 to 140 and then increased by d 254 (3.76, 2.78, 3.39 ± 0.20%, respectively). Thus, stage of pregnancy but not diet affected selected BNC measurements indicating a specific role of BNC as pregnancy progresses. Additional studies are currently underway to investigate expression of vasoactive factors (e.g., endothelial nitric oxide) by the bovine BNC, and if maternal diet can alter the expression of those factors.